BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is frequently complicated by intracranial aneurysms (IAs). However, the genetic factors driving the elevated IA risk in ADPKD remain poorly understood. In this study, we identified a novel PKD1 mutation associated with a remarkably high IA incidence in a large Chinese ADPKD family. METHODS: We conducted whole-exome sequencing in a three-generation Chinese ADPKD family (n = 24) characterized by an unusually high IA prevalence. The pathogenicity of the identified PKD1 variant was validated through comprehensive functional studies, including protein localization, calcium signaling, and endothelial cell behavior analyses. RESULTS: We discovered a novel PKD1 mutation (c.G10086T) that co-segregated with disease in all affected family members. Notably, 38.1% (8/21) of the mutation carriers developed IAs, a significantly higher rate than reported in general ADPKD populations (4%-11.5%). Functional studies revealed that this mutation disrupted polycystin-1 trafficking and impaired calcium signaling, leading to endothelial dysfunction. In vitro experiments demonstrated enhanced angiogenic potential and compromised vascular integrity in cells expressing mutant PKD1. CONCLUSIONS: The newly identified PKD1:c.G10086T mutation represents a high-risk genetic variant for IA development in ADPKD. Our findings provide new insights into the vascular complications of ADPKD and suggest that PKD1 genotyping may help identify patients requiring intensive IA surveillance. This study supports the development of mutation-specific screening strategies for ADPKD-associated vascular complications.